BELMONT, CALIF. — When the City Council of this San Francisco suburb voted to consider what could be the most stringent tobacco regulation in America, anti-smoking activists cheered. Banning smoking everywhere but single-family detached homes and their yards would be a big step forward, even in health-conscious California.

Then the blogosphere erupted. Side-by-side portraits of Councilwoman Coralin Feierbach and Nazi SS chief Heinrich Himmler were posted on a smoking-rights website. Threats were e-mailed to City Hall, and police and prosecutors were called in to investigate.

A strict new ordinance is still set to be unveiled this winter for more public discussion and an eventual vote. But instead of just the flat-out ban on lighting up in apartments, condominiums and public places that captured worldwide attention, City Atty. Marc Zafferano said the first draft would be a menu of restrictions from which council members could pick and choose.

So although Belmont may not make the kind of history envisioned in the early headlines ("Belmont to be first U.S. city to ban all smoking"), it still could make history of another sort, by finding a line this tobacco-averse nation is unwilling to cross — at least for the moment — in pursuit of better public health.

"I don't know where the boundaries of a truly legally defensible ordinance are," acknowledged Councilman Dave Warden, who is pushing to pass "the strictest law possible."

"I really believe that we're really so close to the line that no one can really tell," he said.

Even though nearly two-thirds of Americans have smoke-free policies in their own homes, according to the 2000 census, restrictions on smoking in multi-unit buildings, in the very sanctity of one's own living room, constitute a new frontier in tobacco law.